This invention relates to the field of autonomous sailing vessels, and in particular to a low-cost, highly-efficient, and highly-robust sailboat that includes monitoring and communication equipment for monitoring and reporting environmental and other conditions.
The world's oceans are among the most difficult and expensive regions to monitor, due in part to the size of the area encompassed by the oceans and the time and resources required to reach remote areas. It is estimated that it would cost about $10-100K per day to provide a manned monitoring vessel in a remote area, such as the South Pacific. Accordingly, very little oceanographic monitoring is actually performed. In like manner, aerial reconnaissance can be very expensive, and very limited in terms of the range and area that can be monitored during each flight. Manned monitoring vessels or aircraft are also subject to adverse weather conditions, which may limit the times that the monitoring may be conducted, or may place the monitoring personnel at increased risk. Satellite imaging provides some information regarding the condition on the surface and above the ocean, but is substantially limited with regard to conditions under the ocean surface.
There is an increasing need to provide more detailed oceanographic monitoring. Concerns abound, for example, regarding increasing levels of hydrocarbons and other materials that are harmful to marine life. In coastal areas, nitrogen runoff from fertilized lands is particularly of concern. The monitoring of fish in particular habitats may provide an early-warning of increasing mortality or decreasing birth rate. In like manner, in the event of an environmental disaster, such as the Gulf oil spill, an accurate monitoring of the extent of the effects of the disaster can aid rescue and repair operations.
Beyond environmental concerns, the increase in pirate activities in certain areas of the world is of concern, as well as the increase in drug trafficking via the seas. Manned surveillance is limited in range and area, and in some cases, dangerous to the surveillance crew.
In addition to addressing particular concerns, the monitoring of oceanographic conditions may enhance our ability to forecast storms and tsunamis, and may enhance marine safety by warning vessels of particularly hazardous conditions. In some cases, the availability of remote monitors on the seas in a region may enhance search and rescue operations in that region.
It would be advantageous to provide an affordable means for increasing oceanographic monitoring. It would also be advantageous to be able to provide this increased oceanographic monitoring without requiring personnel at the sites being monitored. It would also be advantageous to provide a reliable and robust monitoring capability with a high likelihood of survivability in hazardous conditions.
These advantages, and others, can be realized by a fleet of autonomous sailing vessels that are equipped with monitoring and communication equipment for reporting environmental and other conditions. For optimal stability and speed, the autonomous sailing vessels are multi-hulled vessels (catamarans) with self-righting capabilities. Each sailing vessel sends and receives information via one or more satellite links, using solar power to power the communications equipment as well as the monitoring equipment. Each sailing vessel includes an auto-sailtrim system to maintain a desired attack angle with the wind (‘angle of attack’), and electric propulsion for use as required when sufficient electric power is available. A modular design is used to support mission-specific payloads.
In an example embodiment, the sailboat comprises a plurality of hulls arranged parallel to each other and coupled together by a truss arrangement, a wingsail structure that is rotatable about a first axis of rotation that is orthogonal to a plane of the hulls, and a second axis of rotation that is parallel to the hulls, and an auto-righting system that is configured to rotate the wingsail structure about the second axis of rotation when a capsize of the sailboat is detected.
The righting of the capsized sailboat may be performed by rotating a buoyant mast structure about an axis that is parallel to a surface of the body of water, so as to move the center of buoyancy of the capsized sailboat beyond a center of gravity of the capsized sailboat.
In another example embodiment, the sailboat comprises a plurality of hulls arranged parallel to each other and coupled together by a truss arrangement, a wingsail structure that is rotatable about a first axis of rotation that is orthogonal to a plane of the hulls, and an autotrim system that controls rotation of the wingsail structure about the first axis of rotation. The wingsail structure includes a wingsail that provides lift to propel the sailboat forward, a wind vane that pivots on the wingsail structure so as to consistently be aligned with a current wind direction, and a coupling rod that controls a difference between an orientation of the wingsail structure and an orientation of the wind vane. The autotrim system includes a cam that is attached to the truss arrangement and coupled to the coupling rod to control the difference between the orientation of the wingsail structure and the orientation of the wind vane based on an orientation of the truss structure.
The self-trimming may be performed by coupling the wingsail structure and the windvane structure via a cam that controls the angle of attack of the wingsail based on the direction of wind indicated by the windvane structure.
Throughout the drawings, the same reference numerals indicate similar or corresponding features or functions. The drawings are included for illustrative purposes and are not intended to limit the scope of the invention.